BATTLE OF CAROLINAS

North Carolina coach Andrew Calder speaks during a news conference at the NCAA college basketball tournament in Stanford, Calif., Saturday, March 29, 2014. North Carolina plays South Carolina in a regional semifinal on Sunday. (AP Photo/Jeff Chiu)

North Carolina guard Diamond DeShields waits for her turn to shoot during practice at the NCAA college basketball tournament in Stanford, Calif., Saturday, March 29, 2014. North Carolina plays South Carolina in a regional semifinal on Sunday. (AP Photo/Marcio Jose Sanchez)

From right to left, North Carolina guard Diamond DeShields speaks next to guard Allisha Gray and forward Xylina McDaniel during a news conference at the NCAA college basketball tournament in Stanford, Calif., Saturday, March 29, 2014. North Carolina plays South Carolina in a regional semifinal on Sunday. (AP Photo/Jeff Chiu)

North Carolina guard Allisha Gray, left, smiles next to guard Diamond DeShields during a news conference at the NCAA college basketball tournament in Stanford, Calif., Saturday, March 29, 2014. North Carolina plays South Carolina in a regional semifinal on Sunday. (AP Photo/Jeff Chiu)

North Carolina players go through shooting drills during practice for the NCAA women's college basketball tournament in Stanford, Calif., Saturday, March 29, 2014. North Carolina plays South Carolina in a regional semifinal on Sunday. (AP Photo/Marcio Jose Sanchez)

North Carolina players go through drills during practice at the NCAA women's college basketball tournament in Stanford, Calif., Saturday, March 29, 2014. North Carolina plays South Carolina in a regional semifinal on Sunday. (AP Photo/Marcio Jose Sanchez)

North Carolina head coach Andrew Calder instructs his team during practice at the NCAA college basketball tournament in Stanford, Calif., Saturday, March 29, 2014. North Carolina plays South Carolina in a regional semifinal on Sunday. (AP Photo/Marcio Jose Sanchez)

North Carolina head coach Andrew Calder, right, goes through post up drills with forward Hillary Summers during practice at the NCAA college basketball tournament in Stanford, Calif., Saturday, March 29, 2014. North Carolina plays South Carolina in a regional semifinal on Sunday. (AP Photo/Marcio Jose Sanchez)

North Carolina forward Xylina McDaniel smiles during a news conference at the NCAA college basketball tournament in Stanford, Calif., Saturday, March 29, 2014. North Carolina plays South Carolina in a regional semifinal on Sunday. (AP Photo/Jeff Chiu)

South Carolina center Alaina Coates smiles while speaking during a news conference at the NCAA college basketball tournament in Stanford, Calif., Saturday, March 29, 2014. South Carolina plays North Carolina in a regional semifinal on Sunday. (AP Photo/Jeff Chiu)

South Carolina guard Tiffany Mitchell, center, speaks while seated between forward Aleighsa Welch, left, and center Alaina Coates during a news conference at the NCAA college basketball tournament in Stanford, Calif., Saturday, March 29, 2014. South Carolina plays North Carolina in a regional semifinal on Sunday. (AP Photo/Jeff Chiu)

South Carolina players huddle during practice at the NCAA college basketball tournament in Stanford, Calif., Saturday, March 29, 2014. South Carolina plays North Carolina in a regional semifinal on Sunday. (AP Photo/Marcio Jose Sanchez)

STANFORD, Calif. —

When Xylina McDaniel was deciding between her two finalists, North Carolina and South Carolina, it came down to a simple equation.

South Carolina was about 25 minutes from her house in Blythewood. North Carolina was more like 3-4 hours.

McDaniel laughed as she told the story Saturday, then called it “the best decision I’ve ever made in my life.”

Today her hometown team and her chosen one will meet on the sport’s biggest stage — the NCAA Tournament.

No. 12 UNC and No. 8 South Carolina will play in the Sweet 16 of the Stanford Regional at Maples Pavilion (7 p.m., ESPN2). And McDaniel, a sophomore forward, is expected to play a big part in the outcome.

The top-seeded Gamecocks (29-4) outrebound opponents by nine a game (the 12th-best margin in the country) and score 50.2 percent of their points in the paint. Fourth-seeded UNC (26-9), which plays a three-guard lineup, know that McDaniel and freshman center Stephanie Mavunga will need to hold their own in the interior for the Tar Heels to advance.

When ACC freshman of the year Diamond DeShields was asked about her matchup with fellow guard Tiffany Mitchell, the SEC player of the year, DeShields instead turned to the matchup inside.

“I understand that this is going to be a game of post play, simply because of the post players they have and the post players we have,” DeShields said. “I don’t think it’s more about what we can do, it’s more about what Xylina can do, and I think she’s going to get the job done. She’ll be all right with that challenge. I’ve got confidence in her.”

The Gamecocks feature all-SEC forward Aleighsa Welch, who averages 13.8 points on 57.4 percent shooting and 7.6 rebounds, and SEC freshman of the year Alaina Coates, a 6-4 center who averages 8.3 rebounds.

“It’s imperative for us to establish our post presence,” Welch said. “It’s been what’s been successful for us all year. … It’s what we’ve been doing all year, and we don’t want to shy away from that, because it’s been what’s worked.”

The Tar Heels will counter with McDaniel (11.6 points, 5.8 rebounds) and Mavunga, a 6-3 post player who led all ACC freshmen on the boards (8.2).

McDaniel, a high school teammate of South Carolina starting wing Asia Dozier at Spring Valley (S.C.) High, isn’t the only Tar Heel with close ties to South Carolina. UNC starting point guard Latifah Coleman played AAU basketball with Mitchell, while Tar Heels backup guard N’Dea Bryant played with Welch at Goose Creek (S.C.) High.

“It makes it a lot more fun for all of us involved, playing with old high school teammates,” Welch said. “A little friendly trash talking, the battle of the Carolinas — it makes it a lot more fun.”

The ties between the border-state rivals even stretch to the bench. Tar Heels assistant coach Ivory Latta, UNC’s all-time leading scorer, grew up rooting for South Carolina. But the McConnells, S.C. native wasn’t recruited by her in-state school until late in her prep career.

“It was pretty funny,” Latta deadpanned. “Hilarious.”

McDaniel estimated that she played with two of the Gamecocks and against four others during her time on the local AAU circuit. She said the first game between the teams this season — the Tar Heels beat the Gamecocks 74-66 in Myrtle Beach on Dec. 18 — was “the most fun I’ve had in a while.”

Mavunga had 20 points and 12 rebounds in that meeting, while McDaniel also had more rebounds (seven) than anyone on South Carolina as UNC won the rebounding battle 43-33 and outscored the Gamecocks 44-36 in the paint. The 74 points are still the most allowed this season by South Carolina.

The first matchup gives UNC confidence, despite the Gamecocks’ higher seed. Today’s winner will face either second-seeded Stanford or third-seeded Penn State in the regional final Tuesday at 9 p.m.

“They are a No. 1 seed, but they are beatable,” McDaniel said. “They have grown as a team since December, but so have we. It’s going to be a pretty good game. Both teams are going to match up well. But, I mean, they are beatable. They’re going to come out with even more intensity.”